Yellow Pine

[Hank Jarrett]

Re: Yellow Pine

I'll get some this weekend of the 41 and the 45 and try to post them (the guys who know me know I can design space craft for NASA but have trouble posting a picture to the group).
Hank

HEY! I still use a slide rule for crying out loud. It got us to the moon the first time, and I think the computers are what is slowing things down this time.

[VictorBravo]

Re: Yellow Pine

Hank I'd also like to see the photos of the parts and assembly of your window frames. Anyone else, I'd also like to see the way the Model 19 and F-19 side windows are done... that will be done as an upgrade on the airplane I'm about to start rebuilding.

[Pearson]

Re: Yellow Pine

Hank,

The plane I am doing the Harer STC on is a 1946 BC12D. I look forward to the pictures. If you could, please send them to neat1s At yahoo.com

Thank you!

[Hank Jarrett]

Re: Yellow Pine

I have the old "glass" and the two pieces of metal that held it in place on each side (4 total). The screws that hold the "glass" go through the two exterior frames, through the edge of the "glass" and into the formed frame. I "hope" the formed frames are out at the airport (going to be a minor panic if they aren't there!) I will get photos of all the parts this weekend (unless I have to go on a scavenger hunt for the frames). When you see the pictures it is pretty easy to see how it all goes together.
A set of paper templates and some measurements and you should be on your way.
Hank

By the way, I don't remember ever seeing what year your plane is. I do also have the drawings for the wood ones on my 41, but I used Poplar and made them thicker and wider to make up for the reduce strength. They are actually significantly stronger than the originals, which were completely rotted away on the 41. The "D" windows in the 41 were held in with screws through the FABRIC and never came loose! The actual flight air loads must be pretty low.

[Pearson]

Re: Yellow Pine

Hank,

I think I will take you up on your offer to send me info on your factory frames. As I mentioned in a PM, a photo of the edge showing where the glass goes in would also be appreciated.

Thanks,

[Hank Jarrett]

Re: Yellow Pine

By the way, just because I are an engineer don't mean I know all da rules! What my IA says, GOES (for me at least). He has NEVER sent me down the wrong path, and always listens before he makes a decision.
Hank
I think I want to adopt him.

[Hank Jarrett]

Re: Yellow Pine

I probably have a conservative IA. He IS trying to keep me safe and he would probably rather have me get it from Taylorcraft. He knows me too well. If I got a shot at it I would probably try and make my own spark plugs. :rolleyes2:
On the material substitution, it isn't the strength of the material (wood) it's the strength of the PART. You can substitute a stronger wood and keep the dimensions the same, OR you can reduce the dimensions of the part so the part strength is the same with the stronger material (better be ready to show your work in the design department and be ready for an official who will deny approval because he doesn't know if you did it right) and you can also use a WEAKER material and INCREASE the dimensions so the part has the same strength (again, better show your work and be ready for raised eyebrows and "NO WAY" from the "BOSS"). I have designed parts all three ways and been successful, but then, I design spacecraft for a living and can back up my work. The easiest way is to use the specified or stronger material and leave the dimensions the same. Never a question on that.
Hank

[Dan Michaels]

Re: Yellow Pine

I think there is some confusion on Owner Produced Parts. You do NOT need an STC, 337 or much of anything else like that to make and use an owner produced part. There are three ways to qualify once you have shown you can't get it from a PMAed source. You can do the design (and meet the original requirements) you can manufacture the part from an existing design, or you can do the quality assurance for the part. When I make my own parts I try to do more than one (just in case the FAA says I didn't meet one of the requirements correctly). If you can demonstrate you can't get the frame from a normal supplier (PMA) and I give you a tracing of an original part, from which you develop a drawing, then you build the part from a sheet of aluminum, followed by a check to make sure the part meets the drawing, you have done all three. That's what I did on my 41 instrument panel. I did all three of the steps, but you actually only have to do one.
Check out FAR 21.303(b)(2). It isn't as hard as you think. Most of us have most of the tools in our garages that Taylor had in his factory when he started. These are pretty simple planes and if he could make them, we should be able to also.
Hank
By the way, the pre-war planes that had the "D" window were mostly made from wood, the metal frames came after the war. Switching from the original to the alternate could be a problem if your IA is a stickler.

The FSDO I talked to said that there is no "If you cannot find the part from manuf. or PMA'd requirement". You have the right to make an owner approved part if you so wish with nothing more than a log book entry. As long as you fulfill the stated requirements. Also changing the type of wood does not require a 337, as long as the wood is stronger than what is called for. A simple "substituted for" in the log book is all that is required.

Dan

[Pearson]

Re: Yellow Pine

Hank,

Please check for my PM on the subject.

[Larry Lyons]

Re: Yellow Pine

Well for what it is worth, I have some yellow pine that is over 50 years old, and tougher then whale hide. If you want to drive a nail through it you must drill a pilot hole first, that is putting it lightly as to how hard it is to work with! Only problem is, I only have it in 2" X 4"s. I would have to look at how much I actually have, we used it to make hand rails about 35 years ago and it was difficult to work with then. However if someone wants to use some I will be glad to look and see just how much I really have. Larry

[Hank Jarrett]

Re: Yellow Pine

I think there is some confusion on Owner Produced Parts. You do NOT need an STC, 337 or much of anything else like that to make and use an owner produced part. There are three ways to qualify once you have shown you can't get it from a PMAed source. You can do the design (and meet the original requirements) you can manufacture the part from an existing design, or you can do the quality assurance for the part. When I make my own parts I try to do more than one (just in case the FAA says I didn't meet one of the requirements correctly). If you can demonstrate you can't get the frame from a normal supplier (PMA) and I give you a tracing of an original part, from which you develop a drawing, then you build the part from a sheet of aluminum, followed by a check to make sure the part meets the drawing, you have done all three. That's what I did on my 41 instrument panel. I did all three of the steps, but you actually only have to do one.
Check out FAR 21.303(b)(2). It isn't as hard as you think. Most of us have most of the tools in our garages that Taylor had in his factory when he started. These are pretty simple planes and if he could make them, we should be able to also.
Hank
By the way, the pre-war planes that had the "D" window were mostly made from wood, the metal frames came after the war. Switching from the original to the alternate could be a problem if your IA is a stickler.

[Robert Lees]

Re: Yellow Pine

Most IA's would not really care if you substituted spruce for pine

And how many would actually KNOW? (present company excepted, of course). I've used 4130 in replacement for 1020 steel; British spec ali for 2024T3; Ash for pine (it smells nicer) and even the head honcho at the CAA Engineering department didn't pick up on it. All non-structural applications, of course.

It'ld be like using automotive fittings on the tailbrace wires, wing brace wires; brakes; fuel fittings, and all those other applications for which commercially-available fittings were used in the original design. Heaven forbid.

[astjp2]

Re: Yellow Pine

So mix them. It wont hurt anything if your IA will allow it. Tim

[Pearson]

Re: Yellow Pine

Part of the problem with using a different kind of wood is that I have already made the hard parts. I have the large radius curved rear part and the front edge already made. I just ran out of wood. I guess I could just start over with spruce, but I was hoping someone knew of somewhere you could just order a piece of wood to be shipped.

[astjp2]

Re: Yellow Pine

Your STC give you the approval to install the frame, your IA could add a 337 for substituting spruce for the yellow pine, or you could just stick it in and forget about it. Most IA's would not really care if you substituted spruce for pine because it is nonstrutcural. Tim